BS 1191-1:1973

Co-operating organizations
Foreword
1 General
  1.1 Scope
  1.2 Definitions
  1.3 Classification
  1.4 Purity
  1.5 Composition
  1.6 Marking
  1.7 Samples for testing and sampling
  1.8 Manufacturer's certificate
2 Quality of the different classes
  2.1 Class A. Plaster of paris
  2.2 Class B. Retarded hemihydrate gypsum plaster
  2.3 Class C. Anhydrous gypsum plaster
  2.4 Class D. Keene's plaster
Appendix A - Determination of chemical composition and loss on
             ignition
Appendix B - Examination for soundness
Appendix C - Method of determining transverse strength
Appendix D - Determination of mechanical resistance by the dropping
             ball test
Appendix E - Determination of expansion
Appendix F - Method of stabilizing classes A and B plasters
Appendix G - Determination of freedom from coarse particles
Appendix H - Examples of typical classification markings required
             by 1.6
Publications referred to

Composition, grading, soundness of Grades A, B, C, D. Transverse strengths of Grades A and B, mechanical resistance of Grades B, C and D. Expansion on setting for Grade B.